Telephone system.



.iwz mmna can E. E. HINRI'CHSEN. TELEPHONE SYSTEM.

APPLICATION FILED OCT. 6, I9I5.

Patented Oct. 31,1916.

4 SNEETS-SHEET I.

E. E. HINRICHSEN. TELEPHONE SYSTEM.

APPLICATION FILED OCT. 6. l9l5- 1,203,336.

Patented 0m. 31,1916.

E. E. HINRICHSEN.

TELEPHONE SYSTEM.

APPLICATION .FILED OCT. 6. I915.

Patented Ot. 31, 1916.

4VSHEETSSHEET a.

Fig. 3.

I HARM/V4! Mai/ML PMMHFD I J @PH In ven/or:

Edward E fimric/ien MtZ/mz/ 1 AI/y i seer manners cor: UNITED STATES PATENT OFFICE.

EDWARD E. HINRICHSEN, OF EAST ORANGE, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS; TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION on NEW YORK.

" TELEPHONE SYSTEM.

Patented Oct. 31, 1916.

Application filed October 6, 1915. Serial No. 54,336.

T 0 all whom itmay concern Be it known that I, Enwann E, HIN- RICHSEN, a. citizen of the United States, re-

siding at East Oran e, in the county of Essex and State of New Jersey, have mvented certain new and useful Improvements in Telephone Systems, of which the following is a full, clear, concise, and exact lescription.

This invention relates to telephone Systems, and moreparticularly to such syS- tems of the type wherein connections are to be established between subscribers statlons terminating in central offices widely separated.

An object of this mvention 1s to provide a. system of this character wherein an opvide improved Signaling means for a sys-.

tem of this character.

A further object of this invention is the provision of such a system in which a trunk circuit between the two central ofiices may be used as the selecting circuit for selecting the desired local-office.

A still further object of this intention is the provision of such a system in which the trunk circuit between'the two central offices may be used as an extension of a call wire circuit (between the second central oflice and an office local thereto), whereby the operator at the first central office may communicate direct .with an operator at the .selected local oflice.

In accordance with this invention, a main trunk circuit extends from one central oflice to a second central office, and local trunk circuits and associated call or order wire circuits extend from the second central office to av plurality of offices local thereto. 1 Apparatus located at the second central ofhcecontrolled over the main trunk circuit by sclecting keys at the first central office selects the "desired, local trunk and connects the associated callwire circuit thereof to the main trunk circuit. After the proper instructions have been transmitted by the operator at the first central office to the operator at the selected local office, the release of the selecting key permits the connection of the main trunk between the first and second central office with the local trunk between thesecond central office and the se drawings illustrating one embodiment of the invention.

To obtain a clear idea of the entire sys tom, the figures should be placed side by side in the following order from left to 1lgl1t,l, 2, e, 4.

The system illustrated in the drawings involves two central ofiices, one to be hereinaftcr. referred to as the first or originating central office, and the other as the sec ond central ofiice. At the first central office there is located toll cord circuit A, shown in Fig. 1.v Between the first and second central oflices there extends a main trunk circuit B, the outgoing end of which is shown in Fig. 2 and the incoming end in Fig. 3. Local trunk circuits O and associatcd call wire or order Wire circuits Dextend from the Second central office to local offices E, F and G. There is one local trunk circuit and one call wire circuit into each localv office. The outgoing ends of the local trunk and call wire circuits are shown at the right of Fig. 3, while the incoming end of one local trunk circuit and one call wire circuit and equipment thereof for local oflice E are shown to the right in Fig. 4. The equipment for the incoming ends of the local trunk circuits and call Wire circuits to F and G are not shown in the drawings.

Since the originating subscribers line forms no part of this invention, it has not been shown in the drawings.

Assuming that the operator at the first central office has received a call, for a subscriber. whose line terminates in local office E, local to the second. central office, the 0per ator will insert calling plug 6 into jack 7 of the main trunk circuit B ,th reb energizing relay -8 over a circuit from battery BEST AVAILABLE con ond cord circuit to the main trunk circuit B during the connection therewith of cordcircuit A. The actuation of relay 12 also causesithe operation of relay 13 over a circuit which may be traced from battery through the winding of relay 13, contact l t of relay 12, and contact 15 of relay 16 to ground. The operation of relay 13 connects negative signaling battery through the normal contact of relay 21, normal contact of relay 23, winding of relay 24, contact 25 of relay 13, one winding of retardation coil 26, ring side of the main trunk circuit B, one winding of retardation coil 27, windings of relays 2S ard 29, and the upper winding of relay 30 to ground through the contact of r'cla 32. Relay 2% operates, short-circuiting-one winding of relay '8, thereupon permitting sullicien't current to flow through the winding ofrelay 9 to cause the actuation of this relay, whereupon lamp 33 in the calling end of the cord circuit A is lighted. llclays28 and 30 are operated by the flow of negative signaling battery, relay 2S causing the operation of relay 34,. which closes its contact 35 placing .ground on the arumture of relay 30. However, the relav Il-l is slow Ill operating, so.

that relay 30 has time to fully operate, openipg its contact 36 before relay 3i closes Its contact 35. thcrclu' preventing the. operation "of relay 3? when the calling plug of the cord is first plugged into the jack of the main trunk circuitf llclay 2!) is a polarized relay and does not operate on negative signaling batteryv v The operator may now actuate listcniug'kov ill to connect the operators telephone set with the cord circuit and actuate the proper selecting key for selecting the desired local olhce.

41. ii and i l indicate the selecting keys, the hey all for selecting local oliu'ell, the key H. for sclcrrirn local ollicc i and the key if) for sele ting hu'ul ollicc (i. The actuation ol' kc) ll grounds the ring side, key lzl grounds both sides and key 43 grounds the lip side of the line. Assuming that the dcsircd subscriber's line terminates in local ollicc l). the operator will depress key H whi h causes the operation of relay 2i over a cilcuil from hath-11v through the winding ol' relay .l. ring side oi" the main trunk circuit. ring contacts of the jack and plug. and ring side of thcicord circuit, to

ground through the contact or" key ll. The operation nip-clay 'l opens ll. normal-roushifting from negative to positive signaling battery. Relay 29 thereupon operates, causing the operation of relay 51 which in turn completes a path for "current through the winding of relay which operates over a circuit from, battery through the winding of relay 52, contact of relayol, contact 5% of relay 37 and contact 35 of'relay 34 to ground. Relays and .51v having operated, relays and 56 now operate over a circuit from battery through the contact of relay 52, winding of relay lower-winding of relay 56, contact 58 of relay 3? and contact 59 of relay 51 to ground -T he operation of relay 56 closes a locking circuit for itself at contact 60, this circuit being from battery through the winding of relay32, winding of relay (31, upper winding of relay 56 contact 60 thereof, contact 62 of relay 63,'contact 64 of relay (55, and the contact of' relay 6? to ground, relay 6? having been: operated by the operation of relay 5:2, Relay is slow in operating so that relay 51 will have time to operate completely before relay 56 can operate. The operation of relay closesits contacts 65, 66 and 16 7, and theoperation of relay (l1 closes its contacts, ektending the main trunk circuit through to thefarmatures of relay 70. Relay 56 also closes its contact 74, causing the operation ofi relays 75 and- 76. Relay 3:2, the circuit of which was closed by the operation of, relay 56, is slow call wire circuit extending-to local ollice E" is not busy, the closure of contactllfi causes the operation'of relay Tl) over a circuit flOll). battery through the contact and left-hand winding of rclayll. contact (31'- of relay winding otrclay 70 and winding of relay T2 to ground. Relay Tl'is marginal and does not operate when included in series with relays TO and 72, but dra-sopcrato when inchided, in circuit with relay 70 only. Relay 70 in operating, completes the ronncctiou of the. main [run-k circuit ll to the call wire circuit extending lrom the second central ollice to local oliice l). llclay T0 iiroperating also closes its contact Tfir which short-circuits relay 12, preventing the operation .thercol'. musing the operation of relay ii. The operator at the iirst central ollicc niaynow communicateto the operat u' at local ollirc l) the number of the line to whiclrmnncction is desired. The operator at local olliwi it now inserts the plug of the local trunk circuit into the jack of the desired subscl'ilur's line. whereupon relay TH is opering so that relay 51 may release first and establish an alternate locking circuit for re-. lays 56 and 61, this circuit being from bat-.

tery through the windings ofrelays 32 and (51, contact (50 and upper winding of relay 56, contact 62 of relay (53, contact 64 of relay 65, contact 79 of relay 51, contact 5i of relay 37 and contact 35 of relay 34: to ground. The release of relays 51 and 52 releases relay 55, which disconnects the main trunk circuit B from the call wire circuit D and connects trunk circuit B with'the local trunk circuit C. Relay 55, in releasing, releases-relays and 71, which restores the call wire circuit D to itsnormal. condition.

The operator at the first central office now restores listening key 40 to its original position and actuates ringing key 80 to connect a source of ringing current 81 to the ring side and ground to the tip side of the calling end of the cord circuit A, whereupon relay 32 is actuated, causing the operation of relays83 and 84. Relay 83, in operating, connects the tip and ring conductors of the main trunk circuit B to the secondary of a transformer 85, the primary of which has been included in closed circuit with a source of alternating current 86 and interrupter 9!) by the operation of relay 84. High frequency current from the secondary of transformer passes through repeating coil 87 and operates relay 88. Relay 89 is normally energized, so, when relay 88 operates, relay 8!) releases, causing the operation of relay 90. Relay 8!) is slow in releasing so that it will notrelease and cause false rings should relay 88 be energized momentarily due to disturbances on the trunk. Relay 90, in operating, connects a source of ringing current 91 through the local trunk circuit C, causing the operation of relay '92, whereupon ielay )3 is energized connecting a source of ringing current 94 at the local otfice E to the called line. Ringing current remains connected to the called line only as long as the operator at the first central ollicc keepsringing key 80 operated.

response to the operation of the call bell at the station, thersubscriber removes the receiver from the switchhook, causing the operatirm'oi supervisory relay 9:") which removes the short circuit of resistance 96, whereupon relay 7;) receives a reduced flow of current and releases. The release of relay 75 removes the short circuit of the" lower winding of relay 30 and resistance 31, thereby reducing the amount of current through relay 24, causing the release thereof.

Relay 30 remains operated. Relay 24, in releasing,-causes the release of relayf), thereby extinguishingsupervisory lamp 33.

At the termination of the conversation, relay 9 is again energized,'relighting supervisory lamp 33, which serves as a disconnect signal to the operator at the first centralofiice. The operator now withdraws the plug 6 from the jack 7 whereupon relays 8, 12, 13 and 24 ofthe outgoing end and relays 28, 34, 30, 32, 61 and 56 of the incoming end of the main trunk circuit B release. Relay 56 in releasing, releases relay 7 (5, which causes the lighting of supervisory signal 77 to turnish'a disconnect signal to the operator at the local office .E, who thereupon withdraws the plug from the jack of the line restoring all apparatus to normal,

Should the desired subscribers line have been one terminating in the local oflice 'F, the operator atthe' first central ofiice would have selected'the local trunk to this office by depressing selecting key 42. Relays 21 and 23 would thereupon operate, relay 21 shift-' ing the polarity of signaling battery, and relay 23 removing the short circuit of re-' sistance 50, releasing relays 24' and 30. The release of relay 24 extinguishes supervisory lamp 233. The changing of the polarity of the signaling battery operates relay, 29 which causes the operation of relay 51, operating relays 52 and 67. The release of relay 30 operates relay 37, whereupon relays 63" and 9 operate, relay 63 completing a lock-' ing circuit through relays 32, 48 and 63. The local ofiice F is now selected, and the main trunk circuit B is connected tothe corresponding call wire circuit extending to the local o'flice F. The remaining operations for completing the connection through to the subscril'ier in local office F is as herein before described.

Should the desired suhscribers line have been one terminating in local otlice G, the operator at the first central oliice would have selected the local trunk .to this oiiice by depressing selecting key 43. Relay 23 would thereupon operate, removing the short circuit from resistance 50, releasing relays 2-l and 30, The release of relay 2-l eX- tinguishes supervisory lamp 333, and the release of relay 30 causes the operation of relay 3 7, and inturn relays 52 and 67, where- Relay 65 the central ofiice to the call wire circuit'extend j circuit D extending to BEST AVAILABLE COP tions. 100 represents a call wire key at one such operators position. Actuation of key 100, if the call wire circuit is not busy, causes the operation of relay 101, over a circuit from battery through the contact and left-handwinding of relay 71, lower contact ofhey 100, and the windings of relays 101 and 102 to ground. Relay 102 does not operate because relay 101 in operating closes its lower alternate contact 103, short-circuit ing relay 102,. causing the operation of relay- 71. Operation of relay 101 also connects operators telephone set at the second ing to the local ofliceE. Relay 71 in operating, removes the normal short circuit of the right-hand winding thereof, thereby including both windings in -circuit-.- Should this call wire circuit have been busy when the operator at the second central oflice actuated key 100, both windings of relay 71 would have been in circuit, thereby preventing the operation of relay 101. Relay 102 would, however, have operated, lighting the lamp 104 and operating relay 105. The lighting of the lamp 104 indicates to the operator that the call wire circuit is in use, j and the operation of relay 105 connects a to the receiver of the operators tele-.

operg tone phone set'which also indica'testo the ator that the call wire circuit is in use.

Should the call wirecircuit D extending to the local ofiice have been in use when the operator at the first central office actuated listening key 40 and selecting key 41 to select the local ofiice E, the prior operation of relay 71 wouldhave prevented the operation of relay 70, but relay 72 would have operated. Relay 72 operating, would have connected a tone to the normalcontacts 106 and 116 of relay 70, wherebysa'tone would have been transmitted to the receiver of the operator's telephone set at the first central office, indicating to this operator that the call wire the local oflice E was in use. f

Suppose that, while a connection isset up through ofiices and the local ofiice E, F or G to a subseribers station of one of these local ofiices, .the operator at the the first central office should receive another call for connection to a subscribers line terminating 111 one of the local ofiices which second connection would necessitate the use of the main trunk circuit B, the operator would insert the calhng plug of a second cord circuit A into ack lOT the main trunk circuit B. No apparatus assdciated' with themain trunk circuit '13 -'isjoperated by the insertion of the callinpfplug, into the ]il0k 107 While another "callmg plug is connected to the jack '7, for the energizing circuit of relay llis open at a conta ct' of relay 8. As soon as the operator at" tli lirst central oliice vifiii 'hfi the first and second central to communicate with the siredlocal office without havingto withdraw the cord Cll'lillltilflll'l thetjack contingencies above 6 iswithdrawn from jack 7. R'elay 8 releases, causing the operation of relay 11, which in turn operates relay 112, connecting tip and ring contacts of jack .107 with tip and ring conductors of the main trunk circuitB and closing the circuit of relay 10; The circuit of relay 16 is carried through the normal contact of relay 13, so that relay 16 will not operate until after relay 13 has completely released, and the circuit of relay 13" 1S likewise carried through the normal contact of relay 16, so that if relay 16 had previously been oper ated, relay 13 would not operate until after the complete release of relay and 16 are slow. in operating in order'that relaysv28 and 34 will have sufficient time to release when a cord circuit is disconnected from one jack while another cord is connected to the other jack. The operation of relay 13 connects negative signaling battery to the ringside of the main trunk-circuit B, operating relays 28 and 30, as when relay cord circuit A with jack 7. The" operator at the first central office may now actuate listening key 40 keyto select the local office inrwhich terminates the'line of the desired subscriber. I

The selecting keys and operators telephone set shown in Fig. 1 are common to anoperators position. The apparatus included 16. Relays 13 and the proper selecting 16 was operated upon the connection of common to an operators position .or to the first central office.

After having ator at the selected local ofliceathe number of the desired having released the selecting key, the operator at the first central oilice may find that the wrong number has been transmitted to the operator at the local office that the wrong local office has been. selectedythat the rightloeal office has been *selected" but that.

the operator thereat has c nnected the local trunk circuit to the wrong subscribeflsline, or the right subscribers liuemay have been connected with but the subscribercdid not respond. In such cases, it is desirable that communicated to the opera subscribers line, and after the first central ofiice operator may be able o erator at the dethe plug of of the mam trunk circuit H Thisisespe- 0nd jack of the main trunk oircuitg va provides for the mentioned. a "Assmmng, a

The present invention for example, that the proper local oilice-has been selected and that the c 'aeratorthcreat has connectedthe anconnng end of thelocai; 53

trunk circuit C to the Wrong subscribers line, and assuming further that the oiiice selected is local ofiice E, the operator at the first central oflice may actuate listening key 40 and selecting key -11, which operates relay 21,-whereupon polarized relay 29 operates, causing in turn the operation of relay 51. The operation of relay 51 opens the locking circuit of relays 5G and 61, which thereupon release. The operation of relay 51. also operates relays 52 and (37, but relay 52 is slow in operating so that it does not close its contact until after relays 56 and 61 have fully operated. Upon the full operation of relay 52, relays 55 and 56 oper-' ate, in the manner hereinbefore described, completing a locking circuit for relay 56 through relays 32 and (i1. Relays and 61 being operated, the main trunk circuit B is connected to the call wire circuit D extending to the local office I), whereupon the operator at the first central oflice may give the proper instructions to 'the operator at the local office E. i

hat is claimed is:

1. A telephone system comprising a trunk circuit-extending from a first to a second central office, call wire circuits, one extending fromthe second central otiice to each of a plurality of local ofiices, a plurality of selecting keys at the first central oflice, means at the second central office selectively responsive to the actuation of one of said keys to connect said trunk circuit with one of said call wire circuits, and a relay operating upon the selection of a local trunk circuit and locked up upon the release of the actuated selecting key to connect the main trunk circuit with theselccted local trunk circuit.

2. In a telephone system, a main trunk circuit extending from a first to a. second central office, local trunk circuits and associated call wire circuits, one of each cxtending from the second central ollicc to each of a plurality of local oil-ices, a plurality of selecting keys at the first central ollice, means at the second central otl'ice selectively responsive to the actuation of any one of said keys to select one of said local trunk circuits, and apparatus cooperating with said means to connect the correspomling call wire circuit with said main trunk circuit.

3. In a. telephone system, a main trunk circuit extending from a first to a second central oll'ice, local trunk circuits and associated call .wire circuits, one of each extending from the second central otlice to each of a plurality of local ollices, a plurality of se-.

lecting keys at the first central otiice, means at the second central oflice selectively responsive to the actuation of any one of said keysto select one of said local trunk circuits, and apparatus cooperating with said means to connect the corresponding call wire circuit with said main trunk circuit,

said apparatus, upon the release of the actuated selecting key, serving to disconnect said call wire circuit from and to connect said selected local trunk circuit with said main trunk; circuit.

4. In a telephone system, a main trunk circuit extending from a first to a second central oflice, local trunk circuits and associated call wire circuits, one of each extending from the second central oilice to each of a plurality of local otiices, a plurality of selecting keys at the first central ofiice, a plurality of relays at the second central office selectively responsive to the actiation of one of said selecting keys and cooperating to select one of said local trunk circuits, and

relays operating upon the selection of a local 1 trunk circuit to connect the corresponding call wire circuit with said main trunk circuit.

In a telephone system, a normally open main trunk circuitextending from a first to a second central oliice, a'link circuit at the first central oliice, local trunk circuits and associated all wire circuits, one of each ex-. tending from the second central oflice to each of a plurality of local ollices, a plurality of selecting keys associated with said link circuit, apparatus operating upon connection of said link with said main trunk-circuit to close said normally open main trunk circuit, means at the second central oflice selectively responsive to the, actuation of any one of i said keys to select one of said local trunk circuits, and apparatus cooperating with said means to connect the corresponding call wire circuit with said main trunk circuit.

(3. In a telephone system, a main trunk circuit extending from a first to a second position, local trunk circuits and associated call wire circuits, one of each extending from the second position to each of a plurality'of other positions. electromagneti-.

cally-controlled mechanism at the second position selectively responsive to currents of different character for selecting one of the local trunk circuits and its associated, call wire circuit. means at the firstv position for determining the character of current for se-- lecting the mechanism,and a relay operating upon the selection of the local trunk circuit and its associated call wirecircnit for connecting the main trunk with the selected call \vire circuit.

7. in a telephone system, a main trunk circuit extending from a first to a second central ollice. local trunk circuits and associated call wire circuits. one of-each extending from the second central ofiice to each of a plurality of'local oliices, a plurality of sclectiiig keys at the first central 'ofiice, a neutral. a polarized and a marginal relay at the second central olllce selectively responsive to the actuation of one of said selectin keys and cooperating to select due of said local trunk circuits, and relays operating upon the selection of the local trunk c1rcu1t to connect the corresponding call wire C1 I- cuit with said main trunk circuit.

8. In a telephone system, a main trunkcircuit-extending from a first to a second central office, local trunk circuits and associated call wire circuits, one of each extending from the second central ofiice to each of a plurality of local oilices, a plurality of selecting keys at the first central ofiice, a neutral, a polarized and a marginal relay'at the second central ofiice selectively responsive to the actuation of one of said selecting keysarid cooperating to select .one of said local trunk circuits and its associated call Wire circuit, two relays operating upon the selection of the local trunk circuitto connect the selected call wire circuit with the main trunk circuit, the release of the actuated selecting key causing one of said last-mentioned relays to release to disconnect the call \vi're circuit from and to connect vthe corresponding local trunk circuit with the main trunk circuit, and a locking circuit for. the other. of the last-1nentioned relays established upon the release of the actuatd'd selecting key.

9. In a telephone system, a main trunk circuit'extending from a first to a second central oflice, local trunk circuits and associated call'wire circuits, one of each extending from the second centraloliice to each of a plurality of local olfices, a plurality of selecting keys at the first central ofiice, a plurality of relays at the second central oflice selectively responsive to currents )of different strength and polarity upon the actuation of one 0 said selecting keys and coi iperating to select one of said local trunk circuits and its associated call wire circuit, and two relays operating upon the selection of the local trunk'and associated call Wire to connect the main trunk with the selected call wire circuit;-

10. A telephone system comprising a main trunk circuit extending from a first to a second central ollice, local trunk circuits, one

selecting key,

each of a plurality ratus connecting the local trunk circuits,

the second central sive to the actuatlon cause the disconnection of local trunk circuits and to trunk circuit corresponding to the actuated selecting key.

11. A telephone system extending from the each of a plurality connecting the main trunk circuits, a plurality at the first central oliice, a relays at the second centra responsive to the actuati keys to cause the release tioned relay and to circuitcorresponding mg key.

12. A telephone system com trunk circuit extending second central oilice,a link circuit connected with'the main trunk at the first central ofiice. and associated call wire circuits, one of each extending'from the seeeach of a pl local oliices, apparatus at the seco oliice connecting the main trunk c local trunk circuits 0nd central oilice to one of the local trunk keys to disconnect th connected local trunk trunk circuit corresponding to and apparatus with said means to circuit corresponding circuit with the main In Witness whereof,

my name this 5th day EDVARI) a plurality of local of one select the 100 with comprising a main trunk circuit extending from a first to a second central office, local-trunk circuits, one

' second central'omce to of local oflices, a, relay one of the local of selecting keys nd a plurality of 1 office selectively on of one of the of the first-incuselect the local trunk to the actuated selecti from a first to circuits, a

trunk circuit.

of October A. I). 191 E. HINRICHSEN.

prising a main urality of; nd central ircuit with plurality of selecting keys at the first central oiiice,. means'atthe second central ollic v D e selectively IOSPOHSLYB to .the actuation of one of the e, main trunk and the and to select the local the actuated cooperating connect the call wire to the selected trunk I hereunto subscribe 

